Breathable respiratory mask

ABSTRACT

A patient interface is disclosed which is comfortable for the user to wear and includes at least in part a moisture permeable or breathable area in the body of the patient interface. In another embodiment the patient interface is a strapless mask that is moulded to fit the contours of a user&#39;s face and maximise the mask-to-skin seal. An adhesive material is bonded to the mask cushion and is stamped in place to form substantially the same shape as the cushion such that it fits the facial contours of the user.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to patient interfaces particularly though notsolely for use in delivering artificial respiration therapy to patientsrequiring respiratory humidification treatment. In particular thepresent invention relates to a mask with a moisture permeable orbreathable body and an improved sealing mechanism.

2. Description of the Related Art

In the art of respiration devices, there are well known variety ofrespiratory masks which cover the nose and/or mouth of a human user inorder to provide a continuous seal around the nasal and/or oral areas ofthe user's face such that gas may be provided at positive pressurewithin the mask for consumption by the user. The uses for such masksrange from high altitude breathing (i.e., aviation applications) tomining and fire fighting applications, to various medical diagnostic andtherapeutic applications.

One application of such a mask is in respiratory humidificationtreatment. This system normally consists of a ventilator, humidifier,breathing circuit and user interface, being a mask. In this form oftreatment humid air is supplied to the patient and as a result of thetemperature difference between the humid air and the surroundingenvironment, the humid air can condense and form water droplets. Incases where treatment is prolonged (up to several days) these dropletsmay form water pools in the mask that can hamper the treatment, increasethe risk of the patient inadvertently inhaling water and may causediscomfort to the patient.

One requisite of such respiratory masks has been that they provide aneffective seal against the user's face to prevent leakage of the gasbeing supplied. Commonly, in prior mask configurations, a goodmask-to-face seal has been attained in many instances only withconsiderable discomfort for the user. This problem is most crucial inthose applications, especially medical applications, which require theuser to wear such a mask continuously for hours or perhaps even days. Insuch situations, the user will not tolerate the mask for long durationsand optimum therapeutic or diagnostic objectives thus will not beachieved, or will be achieved with great difficulty and considerableuser discomfort.

U.S. Pat. No. 6,196,223 and U.S. Pat. No. 6,341,606 are examples ofprior art that attempts to improve the mask system. U.S. Pat. No.5,715,814 is an example of an attempt to improve the mask scalingmechanism.

SUMMARY OF THE INVENTION

It is an object of the present invention to attempt to provide a patientinterface which goes some way to overcoming the abovementioneddisadvantages in the prior art or which will at least provide theindustry with a useful choice.

Accordingly in a first aspect the present invention consists in a devicefor delivering a supply of gases to a user comprising or including: apatient interface, in use in fluid communication with said supply ofgases and adapted to provide a substantially sealed flow path for saidflow of gases to said user, said patient interface including a body anda sealing member configured to in use rest against the face of a user,at least one moisture permeable area in said body.

Preferably said moisture permeable area is breathable.

Preferably said patient interface has headgear adapted to attach to oraround the head of said user.

Preferably said body has a plurality of sliding members connecting saidheadgear to said patient interface when said patient interface isengaged with said user.

Preferably said patient interface body has a plurality of cut-out areasproducing a framework.

Preferably said at least one moisture permeable area is a plurality ofcut-out areas covered with a moisture permeable film, and said body is aframework.

Preferably said moisture permeable film is attached to the inner surfaceof said framework.

Preferably said patient interface has a plurality of slots cut-out ofsaid patient interface body.

Preferably said slots and said patient interface body is covered by saidmoisture permeable film.

Preferably a rigid mesh is attached to the inner surface of saidframework to form said body.

Preferably said moisture permeable film is attached to the inner surfaceof said rigid mesh and said framework.

Preferably said patient interface further includes an adhesive memberstamped to said sealing member configured to in use rest against theface of the user.

Preferably said sealing member in use remains attached to the user'sface for the duration of the treatment.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described withreference to the accompanying drawings.

FIG. 1 is a block diagram of a humidified continuous positive airwaypressure (CPAP system) as might be used in conjunction with the patientinterface of the present invention.

FIG. 2 is an illustration of the patient interface according to a firstembodiment of the present invention.

FIG. 3 is a front view of the patient interface body of FIG. 2 showingthe upper and lower engaging clips, sliding straps and headgearattachment.

FIG. 4 is a rear view of the patient interface of FIG. 2 illustratingthe bead sealing arrangement.

FIG. 5 is a front view of a second embodiment of a patient interface ofthe present invention were the interface body has chevron cut-out areas.

FIG. 6 is a rear view of the patient interface of FIG. 5 illustratingthe bead sealing arrangement.

FIG. 7 is a front view of a third embodiment of a patient interface ofthe present invention were the interface body has a mesh surface.

FIG. 8 is a side view of the sliding strap.

FIG. 9 is a rear view of a fourth embodiment of a patient interfaceillustrating an adhesive attachment that allows the patient interface tobe held on the patient's face without headgear straps or otherattachment means.

FIG. 10 is an exploded view of the patient interface of FIG. 10 showingthe body to cushion locking arrangement.

FIG. 11 is a perspective view of a fifth embodiment of the patientinterface of the present invention, where the patient interface coversthe full face of the user.

FIG. 12 is a rear perspective view of the patient interface of FIG. 12,showing the mask cushion configuration.

FIG. 13 is an exploded view of the patient interface of FIG. 12, showingthe patient interface body and mask cushion separated.

FIG. 14 is a rear view of the patient interface of FIG. 12, showing anadhesive attachment that allows the patient interface to be held on thepatient's face without headgear straps.

FIG. 15 is a front view of a sixth embodiment of the patient interfaceof the present invention were the interface body has a plurality of cutout areas in a chevron configuration.

FIG. 16 is a front view of the patient interface of FIG. 12, showing theupper and lower engaging clips and headgear strap attachment points.

FIG. 17 is a front perspective view of the patient interface of FIG. 12,showing mask attachment to the user's face using headgear straps.

FIG. 18 is a front perspective view of the patient interface of FIG. 12,showing mask attachment to the user's face using sliding straps attachedto headgear straps.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides improvements in the delivery ofrespiratory therapy. In particular a patient interface is describedwhich is comfortable for the user to wear and includes at least in parta moisture permeable and preferably breathable area in the body of thepatient interface. It will be appreciated that the patient interface asdescribed in the preferred embodiment of the present invention can beused in respiratory care generally or with a ventilator but will now bedescribed below with reference to use in a humidified Positive AirwayPressure (PAP) system. It will also be appreciated that the presentinvention can be applied to, nasal masks, oral masks, and combinationnasal-oral masks or full-face masks.

With reference to FIG. 1 a humidified PAP system is shown in which apatient 1 is receiving humidified and pressurised gases through apatient interface 2 connected to a humidified gases transportationpathway or inspiratory conduit 3. It should be understood that deliverysystems could also be continuous, variable or bi-level positive airwaypressure or numerous other forms of respiratory therapy. The inspiratoryconduit 3 is connected to the outlet 4 of a humidification chamber 5which contains a volume of water 6. The inspiratory conduit 3 maycontain heating means or heater wires (not shown) which heat the wallsof the conduit to reduce condensation of humidified gases within theconduit. The humidification chamber 5 is preferably formed from aplastics material and may have a highly heat conductive base (forexample an aluminium base) which is in direct contact with a heaterplate 7 of humidifier 8. The humidifier 8 is provided with control meansor electronic controller 9 which may comprise a microprocessor basedcontroller executing computer software commands stored in associatedmemory.

The controller 9 receives input from sources such as user input means ordial 10 through which a user of the device may, for example, set apredetermined required value (preset value) of humidity or temperatureof the gases supplied to patient 1. The controller may also receiveinput from other sources, for example temperature and/or flow velocitysensors 11 and 12 through connector 13 and heater plate temperaturesensor 14. In response to the user set humidity or temperature valueinput via dial 10 and the other inputs, controller 9 determines when (orto what level) to energise heater plate 7 to heat the water 6 withinhumidification chamber 5. As the volume of water 6 within humidificationchamber 5 is heated, water vapour begins to fill the volume of thechamber above the water's surface and is passed out of thehumidification chamber 5 outlet 4 with the flow of gases (for exampleair) provided from a gases supply means or blower 15 which enters thechamber through inlet 16. Exhaled gases from the patient's mouth arepassed directly to ambient surroundings in FIG. 1 ore returned to theventilator via a return tube (not shown).

The blower 15 is provided with variable pressure regulating means orvariable speed fan 21 which draws air or other gases through blowerinlet 17. The speed of variable speed fan 21 is controlled by electroniccontroller 18 (or alternatively the function of controller 18 could becarried out by controller 9) in response to inputs from controller 9 anda user set predetermined required value (preset value) of pressure orfan speed via dial 19.

Respiratory Mask

According to a first embodiment of the present invention the patientinterface is shown in FIGS. 2, 3 and 4 as a nasal-oral mask. It will beappreciated the patient interface could equally be a nasal mask, oralmask or full-face mask. The mask 2 includes a hollow body 30 with aninlet 31 connected to the inspiratory conduit 3. The mask 2 ispositioned on the face of the user 1 with the headgear 32 secured aroundthe back of the head of the patient 1. The restraining force from theheadgear 32 on the hollow body 30 ensures enough compressive force onthe mask cushion 33, to provide an effective seal against the user'sface.

The hollow body 30 is constructed of a relatively inflexible materialfor example, polycarbonate plastic. Such a material would provide therequisite rigidity as well as being transparent and a relatively goodinsulator. The expiratory gases can be expelled through a valve (notshown) in the mask, a further expiratory conduit (not shown), or anyother such method as is known in the art. The hollow body 30 has areascut out 34 of the front surface such that the hollow body 30substantially consists of a framework 35 having an outer circumferencesurface 36, a vertical member 37 extending from the apex of the outercircumference surface 36 to the apex of the inlet 31, plus an upperhorizontal cross-member 38 and a lower horizontal cross-member 39. Anumber of engaging clips 40 are connected to the upper and lowerhorizontal members 38 and 39 respectively for the attachment of slidingmembers 41 to connect the patient interface 2 to the headgear 32. Amoisture permeable or breathable film 42 is bonded to the inner surfacesof the hollow body frame 35 to cover the cut-out areas 34 in order toprevent or reduce the formation of water droplets inside the mask 2during prolonged humidification treatment thereby allowing moisture toescape to the surrounding environment. A number of techniques exist as ameans of attaching the moisture permeable film 42 to the hollow bodyframe 35 which may include gluing, sonic welding techniques,over-moulding or a snaptight connection between the moisture permeablefilm surface 42 and the hollow body frame 35.

A second embodiment of the patient interface of the present invention isshown in FIGS. 5 and 6. The hollow body 30 is constructed of arelatively inflexible material and comprises a rigid outer circumferencesurface 36 and a front surface 43 to which the inspiratory conduit 3 isattached. The hollow body front surface 43 contains a plurality of slots44 of equal dimension equidistant in the vertical direction about themid-line of the front surface 43 and placed between the upper and lowersets of engaging clips 40 a and 40 b. The slots 44 are formed in aherring bone configuration with the distance between the mid-line of thefront surface 43 to each row of slots increasing from the bottom surfaceof the upper engaging clips 40 a towards the apex of the inlet 31. Amoisture permeable film 42 is bonded to the hollow body 30 on the insidesurface of the front surface 43 covering the slots 44 in order toalleviate the build-up of condensation within the patient interfaceduring prolonged humidification treatment.

A third embodiment of the patient interface of the present invention isshown in FIG. 7. The hollow body 30 is formed in the manner as describedin the preferred embodiment of the present invention. A rigid meshstructure 45 is bonded to the vertical and horizontal members 37, 38 and39 respectively and the outer circumference surface 36. A moisturepermeable film 42 is further bonded to the inside surface of the hollowbody framework 35 and rigid mesh 45 to alleviate the build-up ofcondensation within the patient interface during prolongedhumidification treatment. The rigid mesh 45 provides additional strengthand support to the hollow body framework 35 and a larger surface area onwhich to bond the moisture permeable film 42.

A fourth embodiment of the patient interface may be a full face mask 46,such as shown in FIGS. 11 to 18. The patient interface 2 is capable ofcovering the whole face of the user 1, not merely the nose and/or mouth.The full face mask is constructed of a relatively inflexible materialsuch as polycarbonate plastic. Such a material would provide therequisite rigidity as well as being transparent, a relatively goodinsulator and allows the patient to be monitored and the user to see.The patient interface 2 has a body 47 and a cushion 48, where the bodyincludes at least one cut-out area 49 or window of moisture permeablefilm 42. FIG. 11 illustrates two areas of moisture permeable film 42,but any number of areas or alternatively one large window could beprovided. A rigid mesh structure 45 of the type previously described maybe bonded to the mask body 47 to provide additional support whilst alsoproviding a body to which the moisture permeable film 42 can be adheredto. Alternatively, as shown in FIG. 15, the mask body 47 may have aplurality of slots 60 of the type previously described, providing arigid surface to which the moisture permeable film 42 can be adhered to.

The mask body 47 has a tubular aperture 51 located at the front surface50 from which a tubular extension member 52 protrudes. When in use atube or conduit (not shown) can be attached to the tubular extension 51to allow gases to be supplied to the interior of the patient interface 2during treatment. The mask cushion 48 is of similar configuration tothat described in relation to the nasal masks, oral masks andcombination nasal-oral masks but extends around and fits the contours ofthe periphery of the user's face 1.

In other forms of the patient interface 2 of the present inventiondifferent configurations of the cut-out areas 34 and the placement ofthe moisture permeable film 42 on the mask body 30 can be vaneddepending on the size and application of the patient interface.

Moisture Permeable Film

The moisture permeable or breathable film 42 bonded to the interior ofthe patient interface 2 of the present invention is preferably aflexible and breathable membrane that allows water vapour to passthrough it but not condensed water. In particular, the moisturepermeable film 42 may be a hydrophilic polyester block copolymer, suchas SYMPATEX®, or a perfluorosulfonate ionomer membrane, such as NAFION®.

Mask Seal

Referring now to FIGS. 9 and 10, a mask cushion 33 is attached to theperiphery of the hollow body 30 to provide an effective seal onto theface of the user 1 to prevent leakage. The mask cushion 33 is shaped,and is dependent on the mask type, to approximately follow the contoursof a patient's face. The mask cushion 33 will deform when pressure isapplied by the headgear 32 to adapt to the individual contours of anyparticular user.

In FIG. 10 we see that the mask cushion 33 is composed of an inner foamcushion 52 covered by an outer sealing sheath 53. The inner cushion 52is constructed of a resilient material for example polyurethane foam, todistribute the pressure evenly along the seal around the user's face.The inner cushion 52 is located around the outer periphery 54 of theopen face 55 of the hollow body 30. Similarly the outer sheath 53 may becommonly attached at its base 56 to the periphery 54 and loosely coversover the top of the inner cushion 52.

The outer sheath 53 fits in place over the cushion 52, holding it inplace. The sheath 53 is secured by a snap-fit 57 to the periphery 54 ofthe hollow body 30. In FIG. 10 the periphery 54 is shown including anouter bead 58. The sheath 53 includes a matching bead 59, whereby oncestretched around the periphery 54; the two beads 58 and 59 engage tohold the sheath 53 in place.

In the alternative embodiment shown in FIG. 9, the patient interface 1is a strapless face mask 60 which is moulded to fit the contours of auser's face and maximise the mask-to-skin seal. An adhesive material 61is bonded to the mask cushion 33 and is stamped in place to formsubstantially the same shape as the inner cushion 52 such that it fitsthe facial contours of the user 1. The inner cushion surface 52 isprotected by a layer of cover tape (not shown) prior to use in order tomaintain the adhesive properties of the adhesive material 61. Whenrequired for use the cover tape 62 is removed to reveal the adhesivematerial 61 on the inner cushion surface 52. The mask cushion 33 isthereby adhered to the user's face reducing the amount of leakage fromthe mask 60 and increasing the user's comfort by negating therequirement of the user wearing headgear. It is the intention for themask cushion 33 of the alternative embodiment of the present inventionto remain attached to the user's face for the duration of thehumidification respiratory treatment. This system would allow for quickremoval of the hollow body 30, enable other treatments to beadministered with minimal disruption to the user 1 and increase usercomfort by substantially reducing the compressive force of the patientinterface 2 on the user's face.

The strapless face mask configuration as disclosed may also be appliedto the full-face mask 46 as shown in FIG. 14. The adhesive material 61is adhered to the mask cushion 48 which is shaped to fit the contours ofthe user's face thereby increasing user comfort and reducing the amountof gas leakage from the mask 46.

In other forms the mask cushion may be a solid cushion stamped, forexample, from silicon or other similar material. Such a silicon cushionwould be shaped to fit a user's facial contours and in some forms havean adhesive layer applied to allow the cushion to be adhered to theuser's face for the duration of the treatment.

Headgear

To further ensure user comfort and effective pressure on the maskcushion 33, the headgear 32 may be constructed either using two straps32 a and 32 b running around the back of the user's head as shown inFIG. 2 or with a partial skull cap or any other configurations as areknown in the art. In this case the straps 32 a and 32 b or partial skullcap would be constructed using neoprene but may also be constructedusing any material as is known in the art which will be comfortable forthe user.

Hollow Body to Headgear Attachment

Referring now to FIG. 3 the present invention is illustrated using anupper and lower sliding strap 41 to attach the headgear 32 to the hollowbody 30. The strap 41, shown in FIG. 8 in isolation, is constructed ofpolyacetal (Dehin 500P NC010) using injection moulding techniques togive a polished finish. This material is similar to other nylon basedderivatives, with its polished finish having a particularly low frictionco-efficient, and therefore slides with respect to the hollow body 30with very little resistance.

As shown in FIG. 3, the hollow body 30 includes a number of engagingclips 40 connected to the upper and lower horizontal members 38 and 39respectively ensuring adequate direct force on the mask cushion 33 tothe user's face thereby minimizing mask-to-skin leaks. In use thesliding strap 41 snaps into place into engaging clips 40 and can only beremoved therefrom using a substantial force. This means that with anynormal use the sliding strap 41 will stay retained within the engagingclips 40.

FIG. 8 illustrates the sliding strap which is described in ourco-pending New Zealand application number 514184 and is herein describedby way of reference. The sliding strap includes a mid-section 204intended to reciprocate with the engaging clips 40, terminated at eachend by loops 206, 208 which attach to the headgear 32. The first loop206 is a full loop through which the headgear 32 may be permanentlyattached with for example, a Velcro™ strap. The loop 208 at the otherend, is a partial loop 210 designed so that a strap or loop from theheadgear 32 can be easily slipped in or out of the open section 212 toallow easy removal and attachment of the mask.

The present invention as shown in FIG. 3 uses two sliding straps 41which are terminated at each end by loops 208 being partial loops 210.This sliding strap configuration is used to allow easy connection to theheadgear straps 32 plus removal and attachment of the mask.

Referring now to the fourth embodiment of the present invention. FIG. 16shows a full-face mask 46 having an upper and lower set of engagingclips 40 attached to the mask front surface 47. In use the slidingstraps 41 as previously described in the present invention, snap intoplace into the engaging clips 40. The mask front surface 47 also showsan upper and lower set of headgear attachment points 65 permanentlyfixed to the upper portion and lower portion of the periphery of thefront surface 47 which in use Velcro™ straps, connected to the endportion of the headgear straps 66, may be attached.

Full Face Mask Headgear

In a further form of the present invention the headgear assemblycomprises an upper and a lower adjustable strap member 66 which runsaround the back of the user's head 1 as shown in FIG. 17. In this casethe straps 66 would be constructed using neoprene but may also beconstructed using any material as is known in the art which will becomfortable for the user 1. As illustrated in FIG. 17, two sets ofheadgear attachment points 65 are permanently fixed to the periphery ofthe upper portion and lower portion of the full-face mask 46 to whichthe upper and lower adjustable straps 66 are attached. Headgearadjustment means is achieved using Velcro™ near the end portions of theupper and lower straps 66 to ensure user comfort and effective pressureon the mask cushion 48 to minimize gas leakage from the mask 46.

Referring now to FIG. 18 an alternative form of the present invention isshown using an upper and lower sliding strap 41 to attach the headgear67 to the full-face mask front surface 47. In use, the sliding straps 41snap into the upper and lower engaging clips 40. The sliding straps areterminated at each end by partial loops 210 so that a strap or loop fromthe upper and lower headgear members 67 can be easily slipped in or outof the open section 212 to allow easy removal and attachment of thefull-face mask 46. Headgear adjustment means is achieved using Velcro™near the end portions of the upper and lower straps 67 to ensure usercomfort and effective pressure on the mask cushion 48 to minimize gasleakage from the mask 46.

1. (canceled)
 2. A patient interface comprising: a rigid body adapted toform a seal with a user's face; a mask cushion attached to the rigidbody and configured to contact the user's face and provide a sealagainst the user's face; an inlet positioned on the rigid body, theinlet defining a coupling for fluid connection to a gas delivery system;a water vapor breathable layer that is provided to the body to allowwater vapor to pass through but not condensed water, whereby the watervapor breathable layer alleviates the build up of condensation withinthe body.
 3. The patient interface as claimed in claim 2 wherein therigid body comprises at least one cut out area, the water vaporbreathable layer being attached to rigid body, and rigid body defining ahollow body to define a breathing chamber.
 4. The patient interface asclaimed in claim 3 wherein each cut out area is covered by the watervapor breathable layer.
 5. The patient interface as claimed in claim 3wherein the cut out area is a slot cut-out in the rigid body.
 6. Thepatient interface as claimed in claim 3 wherein the cut out areacomprises a plurality of slots of equal dimension equidistant in thevertical direction about the mid-line of the front surface.
 7. Thepatient interface as claimed in claim 3 wherein the cut-out areacomprises a plurality of openings that are formed such that the rigidbody defines a framework.
 8. The patient interface as claimed in claim 7wherein the framework comprises an outer circumferential surface, avertical member extending from an apex of the outer circumferentialsurface to an apex of the inlet, an upper horizontal cross member and alower horizontal cross member.
 9. The patient interface as claimed inclaim 2 wherein the rigid body includes an inner surface and a rigidmesh, the rigid mesh attached to the inner surface.
 10. The patientinterface as claimed in claim 9 wherein the rigid mesh is bonded to thevertical and horizontal members and to the outer circumferential surfaceand the water vapor breathable layer is bonded to an underside of therigid mesh.
 11. The patient interface of claim 7 wherein the pluralityof openings are formed in a herring bone configuration.
 12. The patientinterface as claimed in claim 2 wherein the water vapor breathable layeris disposed on an inner side of the rigid body such that the water vaporbreathable layer overlies at least one cut out in the rigid body. 13.The patient interface as claimed in claim 2 wherein the water vaporbreathable layer is a moisture permeable film.
 14. The patient interfaceas claimed in claim 13 wherein the moisture permeable film is attachedto an inner surface of the rigid mesh.
 15. The patient interface asclaimed in claim 2 wherein the water vapor breathable layer is watervapor permeable but air impermeable, allowing water vapor to passthrough while not allowing the transmission of air.
 16. The patientinterface as claimed in 15 wherein the moisture permeable film isconfigured to allow the passage of water vapor out of the rigid body,while not allowing the passage of air from the rigid body.
 17. Thepatient interface as per claim 13 wherein the moisture permeable film isbonded to an underside of the mesh structure.
 18. The patient interfaceas claimed in claim 2 further comprising including a headgear adapted tohold the patient interface in position on a head of the user.
 19. Thepatient interface as claimed in claim 18 wherein the interface comprisesa slide member mounted to the rigid body in use and adapted to connectthe headgear to the patient interface when a user is using the patientinterface.
 20. The patient interface as claimed in claim 2 wherein thewater vapor breathable layer is a moisture permeable film formed of ahydrophilic polyester block copolymer or perfluorosulfonate ionomermembrane.
 21. A device for delivering a supply of gases to a usercomprising: a patient interface, in use in fluid communication with thesupply of gases and adapted to provide a substantially sealed flow pathfor the flow of gases to the user, the patient interface comprising; abody and a sealing member configured to, in use, rest against the faceof the user, at least one moisture permeable and air impermeable area inthe body of the interface, and a headgear configured to connect to thebody and provide a restraining force to hold the interface on the faceof the user.